topic Re: gen the kernel before a system reboot in Operating System - HP-UX

gen the kernel before a system reboot

Andrew Kaplan — Tue, 15 Dec 2009 17:29:09 GMT

Hi there --

One of our systems, running HP-UX 11.00, is going to be rebooted after being up continuously for over 500 days. Prior to the reboot, it was suggested by an HP technician that we "gen the kernel" to be sure that we can create a valid bootable kernel.

I have not heard of this step, nor the commands that are involved with it. I was hoping someone would know what this is, what the command(s) are, and what it entails.

Thanks.

Re: gen the kernel before a system reboot

Pete Randall — Tue, 15 Dec 2009 17:32:16 GMT

If you're unfamiliar with gen'ing a kernel, the easy answer is to use SAM. It will gen the kernel and then ask if you want to reboot. Answer yes and the reboot will happen or you can leave the question there until you're ready.

Pete

Re: gen the kernel before a system reboot

Patrick Wallek — Tue, 15 Dec 2009 17:32:49 GMT

I'm not sure why they would tell you that.

IF the system has been up and stable, and
IF no PHKL, or other patches requiring kernel updates have been installed,
I wouldn't really worry about it.

What is the time stamp of the /stand/vmunix file? Is it the same as, or older than, the last time the system was booted? If so, I wouldn't regen the kernel.

Re: gen the kernel before a system reboot

Michael Steele_2 — Tue, 15 Dec 2009 17:46:16 GMT

Hi

Never heard that one. I know of boxes, especially workstations, that stay up for 1000 days and then reboot just fine. No difference. No problem.

I would even say you got bad advice from someone how shouldn't be giving you advice, and commend you for recognizing the bad advice and double checking.

There are people on this forum with lifetimes of expertise in HP-UX, verses paid for support from Costa Rica that uses people who can hardly speak English, or people who never heard the word "HP-UX" before they got their current job.

Re: gen the kernel before a system reboot

Andrew Kaplan — Tue, 15 Dec 2009 18:03:15 GMT

Hi there --

Thanks for that vote of confidence. At this point I am going to hold off on the "gen the kernel" and reboot option.

This issue did give me an idea: Maybe there is a(re) runaway process(es) that is/are taking up swap space and causing this issue. To that end, is there a command that I can use that would show what processes are taking up the most swap space? Thanks.

Re: gen the kernel before a system reboot

Pete Randall — Tue, 15 Dec 2009 18:05:11 GMT

Patrick and Michael both make excellent points but I don't see what it would harm. I've been stuck with a kernel that wouldn't gen and it was not a pleasant experience.

To me, this sounds totally unnecessary, but reassuring. Maybe you could flip a coin.

Pete

Re: gen the kernel before a system reboot

Michael Steele_2 — Tue, 15 Dec 2009 18:23:02 GMT

Hi

Could you open another thread? I'm concerned that other members will miss your newest question and consider this thread closed.

Don't forget to assign 0 to 10 points and close the thread. Sometimes they get responded to years after being posted. (* yep, it does happen *)

Re: gen the kernel before a system reboot

Andrew Kaplan — Tue, 15 Dec 2009 18:25:33 GMT

Thanks to everyone for the advice. I am opening a separate ticket to determine what processes are taking up the most swap file space.

Re: gen the kernel before a system reboot

Dennis Handly — Tue, 22 Dec 2009 10:02:32 GMT

Here is a possible reason for periodic regen of the kernel. Not sure how the files in /usr/conf/ got corrupted? The regen would catch this sooner, rather than having months of ignite backups of useless files.
http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1395486